1. Field of the Invention
The invention pertains to a crawler, in which at least two crawler assemblies are arranged parallel to each other, and in which each crawler assembly has a longitudinal beam; a caterpillar track, which travels around the longitudinal beam in the longitudinal direction of the beam and which has an upper run and a lower run; at least one drive mechanism consisting of a motor, a gearbox, and a drive sprocket, which meshes with the caterpillar track; and an idler wheel, the position of which can be shifted relative to the stationary part of the longitudinal beam to tighten the track.
In the development of mobile cranes with very large capacities, it is necessary to take into consideration not only the changes in the load-bearing parts of the crane but also those in the parts which provide mobility, namely, the crawlers.
2. Description of the Related Art
For mobile cranes of this class, which have a high intrinsic weight and which also must be able to move under maximum load, it is essential that suitable and powerful drives be installed in the crawler assemblies, namely, drives which can provide the necessary forward drive forces (drive power). Drives suitable for these larger cranes are available on the market but not in all sizes. It is therefore not possible to purchase an appropriately sized drive to fulfill all of the possible requirements.